1. Field of the Invention
The invention relates to the field of recovering scrap metal from soil. More particularly, the invention relates to mobile apparatuses which are usable for recovering scrap metal from scrap metal-contaminated soil and methods related thereto. The invention also relates to the field of business methods involving the scrap metal recovery business.
2. Background
The soil of scrap yards, recycling centers, landfills, and other areas where large quantities of scrap metal are handled becomes, over time, contaminated with bits and pieces of the scrap metal that was handled there. The amount of scrap metal that becomes mixed into the soil varies with the nature of the operation taking place near or on the soil. For example, the areas in the vicinity of automobile shredders are particularly susceptible to becoming embedded with large amounts of scrap metal. Also, the care with which the scrap metal is handled and transported across the soil impacts the amount scrap metal that gets left behind and commingled with the soil. Scrap metal-contaminated soil may also be mixed in with the scrap or refuse when it arrives by transport vehicle.
Typically, the scrap metal-contaminated soil eventually gets segregated into piles for transport to landfills for disposal. This may happen at any time during the life cycle of the scrap yard, recycling center, et cetera, (hereinafter and in the appended claims referred to individually and collectively as a “handling facility”), but most generally occurs after operations at the handling facility have been terminated and the site is being rehabilitated for another use. The transport of the scrap metal-contaminated soil entails a high transportation cost, especially if the disposal site is distant. The disposal fee is also high because of the presence of the scrap metal.
Where the economic incentive is large enough, a scrap metal recovery plant may be constructed on the site of the handling facility to remove the scrap metal contaminants from the soil. The inventor of the present invention configured and installed such a recovery plant, which became operational in 2000, at a closed handling facility in New Hampshire. The recovery plant took about a month to construct on site and cost over $800,000 to install. The recovery plant included a vibratory bed soil screener station, a magnetic separator, a vibratory feeder, an eddy current separator, a manual picking station, and several conveyor belts. The scrap metal-contaminated soil was fed into the screener station where it was screened into two substreams, a coarser one which contained the material that did not pass through the 1½ inch opening screen of the screening station and a finer one that contained the material that passed through the screen. The finer substream was fed by a conveyor belt to a magnetic separator to remove the magnet attractable scrap metal and then via a vibratory feeder into an eddy current separator to remove the separable non-magnet attractable scrap metal. Another conveyor belt then transported the finer substream to a picking station where identifiable pieces of remaining scrap metals, such as stainless steel, insulated copper, and lead, were manually removed. After processing, the cleaned, residuary soil of the finer substream was disposed of on-site.
Recovery plants employing some combination of one or more items selected from the group consisting of screeners, magnetic separators, vibratory feeders, eddy current separators, manual picking stations, and conveyor belts have been known in the art for treating non-sorted refuse material streams which do not include scrap metal-contaminated soil as a primary component. For example, U.S. Pat. No. 5,184,780 to Wiens, issued Feb. 9, 1993, discloses a fixed plant system and process for treating solid waste that includes a trommel screen, several magnetic separators, a manual picking station, an eddy current separator, conveyors, and several other pieces of equipment. In another example, U.S. Pat. No. 6,974,097 B2 to Simon et al., issued Dec. 13, 2005, discloses a method for providing an alternative cover for landfills from materials in a recycling operation which includes, inter alia, passing at least a part of the material stream through magnetic separators and a trommel screener.
In many cases, however, the economic incentive is not sufficiently high to justify the installation of a recovery plant at a handling facility for recovering scrap metal from scrap metal-contaminated soil. Even in the cases where the economic justification is sufficient, the processing costs will increase as the distance of the recovery plant from the scrap metal-contaminated soil increases as soils from more distant areas of the handling facility are processed. Also, when the last of the soil that is economically viable to process has been processed, the recovery plant must be decommissioned and then either removed and reassembled elsewhere, its components sold for reuse or scrap, or simply abandoned. In any case, a significant economic cost is incurred at the recovery plant's end stage.
What is needed is an economical method of recovering scrap metal from the scrap metal-contaminated soils of handling facilities. What is needed is a means of processing the scrap metal-contaminated soils that diminishes the costs associated with conventional recovery plants. These needs have existed for decades, but heretofore have gone unsatisfied.
Up until now, the business of scrap metal recovery from scrap metal-contaminated handling facility soils has focused on employing business plans which involve either the construction of a fixed recovery plant at the handling facility or the transportation of the scrap metal-contaminated soil to a remote fixed recovery plant for processing. Such business plans involve a high threshold level for economic viability due to the capital equipment investment costs and risks and/or transportation costs involved. What is needed is a business plan which lowers both the economic threshold for viable scrap recovery and the level of risk involved. This, too, is a long-felt need that has heretofore gone unsatisfied.